I don't know if it's already a feature, but since some of the stuff from this mod reminds me of Netherite,
would you be able to make it so that certain lava items are not burnable?
I know it's not the most original thing suggesting armor, but it would kinda work for how you do get the lava coal.
Rather than just making the armor out of coal, maybe have some sort of recipe with 8 of the lava coal around a diamond/iron/gold to create a lava infused gem/ingot, which can do 1024 operations, but can also be crafted into a full set of armor. When crafted they come with innate fire protection, or, when worn as a full set, gives a permanent fire resistance potion buff.
As well, you could make fire resistance potions from using the lavacoal in a brewing stand.